Sorry no additional info. This was something that I was looking up the other day as well. Please post some pictures when you do the job. One thing I wondered was how does the tank mount and if there is a difference between the various acerbis tanks, XR, XRL... With the Acerbis Dr350 4.2 tank you really only get 200 miles out of it. 4.2 gallons is a joke. Sputtering to a stop with both petcoks on res I can get 3.75 gallons out of it . Using only the right side petcock (since I busted the lever off the left side with a flying rock and now need to use a pair of pliers to open and close, I mainly use the right) I get about 3.3 gallons on res, a little more if I am on pavement, but steep downhill trails it will start to stumble at 3 gallons. So let's say 3.5 gallons. 60 mpg is about what I get on the bike. 70 if it is all road geared high, 50 all trail geared low. 210 miles. Though 200 miles is fine for most things I often do desert 4 wheeling/camping trips where we would do 400 miles between gas stops. I often dream of doing these kind of trips on my DR. But the fuel range really doesn't make it possible. Sure I carry jerry cans in the truck and will need to on the bike. I'd imagine that with a 5.8 tank you will probably only get one more useable gallon out of the deal compared with the 4.2. 1.6 gallons more capacity, but the extra vol is in those giant forward lobes. They look like they are extended at the same angle which means they will most likey trap more gas than the 4.2. ??? I don't know . Just the day dreams of a desk jockey. On second look the XR tank lobes do not look like they hang down as far as the DR's. Since you lose about 1/2 a gallon with the 4.2, assume the same lose with the 5.8, that is 5.2 useable gallons yielding 300 miles.